1 /*
2  * [The "BSD licence"]
3  * Copyright (c) 2011 Terence Parr
4  * All rights reserved.
5  *
6  * Conversion to C#:
7  * Copyright (c) 2011 Sam Harwell, Pixel Mine, Inc.
8  * All rights reserved.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. The name of the author may not be used to endorse or promote products
19  *    derived from this software without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
22  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
23  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
24  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
25  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
26  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
30  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31  */
32 
33 namespace Antlr.Runtime.Tree
34 {
35 
36     /** <summary>
37      *  A TreeAdaptor that works with any Tree implementation.  It provides
38      *  really just factory methods; all the work is done by BaseTreeAdaptor.
39      *  If you would like to have different tokens created than ClassicToken
40      *  objects, you need to override this and then set the parser tree adaptor to
41      *  use your subclass.
42      *  </summary>
43      *
44      *  <remarks>
45      *  To get your parser to build nodes of a different type, override
46      *  create(Token), errorNode(), and to be safe, YourTreeClass.dupNode().
47      *  dupNode is called to duplicate nodes during rewrite operations.
48      *  </remarks>
49      */
50     public class CommonTreeAdaptor : BaseTreeAdaptor
51     {
Create( IToken payload )52         public override object Create( IToken payload )
53         {
54             return new CommonTree( payload );
55         }
56 
57         /** <summary>
58          *  Tell me how to create a token for use with imaginary token nodes.
59          *  For example, there is probably no input symbol associated with imaginary
60          *  token DECL, but you need to create it as a payload or whatever for
61          *  the DECL node as in ^(DECL type ID).
62          *  </summary>
63          *
64          *  <remarks>
65          *  If you care what the token payload objects' type is, you should
66          *  override this method and any other createToken variant.
67          *  </remarks>
68          */
CreateToken( int tokenType, string text )69         public override IToken CreateToken( int tokenType, string text )
70         {
71             return new CommonToken( tokenType, text );
72         }
73 
74         /** <summary>
75          *  Tell me how to create a token for use with imaginary token nodes.
76          *  For example, there is probably no input symbol associated with imaginary
77          *  token DECL, but you need to create it as a payload or whatever for
78          *  the DECL node as in ^(DECL type ID).
79          *  </summary>
80          *
81          *  <remarks>
82          *  This is a variant of createToken where the new token is derived from
83          *  an actual real input token.  Typically this is for converting '{'
84          *  tokens to BLOCK etc...  You'll see
85          *
86          *    r : lc='{' ID+ '}' -> ^(BLOCK[$lc] ID+) ;
87          *
88          *  If you care what the token payload objects' type is, you should
89          *  override this method and any other createToken variant.
90          *  </remarks>
91          */
CreateToken( IToken fromToken )92         public override IToken CreateToken( IToken fromToken )
93         {
94             return new CommonToken( fromToken );
95         }
96 
97         /** <summary>
98          *  What is the Token associated with this node?  If
99          *  you are not using CommonTree, then you must
100          *  override this in your own adaptor.
101          *  </summary>
102          */
GetToken( object t )103         public override IToken GetToken( object t )
104         {
105             if ( t is CommonTree )
106             {
107                 return ( (CommonTree)t ).Token;
108             }
109             return null; // no idea what to do
110         }
111     }
112 }
113